+ Hyperdrive Building Protocol

Neurons are small, and the electrical pulses they generate are even smaller. Luckily, minds greater than my own have come up with a clever way to stick micron sized wires deep into whatever part of the (rat, mouse, etc.) brain that your grant lets you study. These wires can't operate on their own, and need an apparatus to guide, raise/lower, and read the electrical signal from the wire. This is where the drive comes in, so lets learn how to make one.

Background

As mentioned above, there are 3 main purposes of the drive. First, it serves as a mechanism of congregating the wires or tetrodes (4 wires spun together) in a concise​ area. Secondly, it creates a means to lower the tetrodes at certain distances. Third, it serves as a means to read the signals from the wires, and send them to the computer by means of the EIB chip. The Image below serves as a rough idea of what an ideal drive would look like. Luckily, that complex looking piece of technology below comes prebuilt, or it will, in the distant future when things become vastly cheaper. Until then, grab your tweezers, because the whole darn thing is hand built.

Tour of the Drive

Using the general schematic above for reference,

Assembling the Drive

Tetrode Assembly

Supplies

• • 2 sheets of white 8x10 inch paper 

  • Tape 

  • Ruler 

  • Tetrode wire 

  • Scissors 

  • Ceramic Tweezers 

  • Tetrode machine 

  • Heat Gun 

Directions

• 1. Place the 2 sheets of paper side by side on the lab bench and tape them together 

  2. Using the ruler, measure 40 cm and mark the start and end 

  3. Take the tetrode wire and measure out 40 cm using the marked paper and cut using the scissors Be careful not to damage the tetrode wire as you undwind it off the spool 

  4. Place the tetrode spool back in the box and out of the way 

  5. Pick up the wire making sure you do not roll or loop the wire; it is suggested that you lick your fingers and press down on the wire to help it stick to your finger to pick it up 

  6. Fold the wire once in half, holding the two loose ends between your fingers 

  7. Then using the scissors cut the wire at the apex of the loop. 

  8. Once again without rolling or looping the wire, firmly press together the ends to have them stick together 

  9. Lick your fingers and run your fingers toward the loop, pressing the loop together on the way down 

  10. Fold the wire in half once more following the same procedure 

  11. Optional: you can cut the loop remaining at the loose ends to aid in folding 

  12. Use the clamps that come with the tetrode machine to clamp the loose end of the tetrode 

  13. Place the loop on the hook that is on the tetrode machine with the clamp hanging down between the screws at the bottom 

  14. Plug in the machine and press the red button at the top to start spinning 

  15. Once the spinning is complete, get the blow-dryer and place on heat setting 9 and allow to fully heat before using on the tetrode 

  16. Once fully heated, run the heat gun as close to the tetrode as possible without touching down twice (4 times along the length total) 

  17. Let the tetrode cool for at least 45 seconds 

  18. Gently holding the hook at the top, cut the tetrode where it meets the clamp at the bottom 

  19. Using the ceramic tweezers, grab the tetrode gently off the hook 

  20. For quality check, hold up the tetrode and see that it can stand on its own 

  21. If it can, place in the container 

  22. Repeat 

Top Building

Supplies:

• • ​23 gauge wire 

  • 00-90 Brass screws with Hex heads 

  • 00-90 Brass Hex nuts 

  • Dremel 

  • Plastic steel epoxy 

  • Ultra Liquid control super glue 

  • Delrin 

  • Cup 

  • Weigh boats 

  • Flat head pliers 

Directions

• 1. 1. Top building begins with dremeling down the head of the 00-90 Brass screw 

Disk Building

Supplies:

• • ​Brass mold (2 pieces) 

  • 1 large silver screw that goes in the middle of the mold 

  • 3 smaller silver screws that go into the sides of the mold 

  • 00-90 Brass screws with Hex heads 

  • 00-90 Brass Hex nuts 

  • WD-40 

  • Weigh boats 

  • Ease release 200 

  • Screwdriver 

  • Smooth Cast 300- Fast setting 

  • Freshly cut 23 gauge for disc building 

  • 19 gauge for disc building 

  • Flat head pliers 

Bundle A​ssembly

Supplies:

• • ​6mm wire 

  • 30 gauge wire 

  • Finished 6mm in 30 gauge wire 

  • 16 gauge wire 

  • 15 gauge wire 

  • Flat head pliers 

  • 5 minute Epoxy- Clear 

  • Weigh boats 

  • Stirring apparatus 

  • Dremel 

  • Tweezers 

  • Microscope 

  • 19 gauge 

EIB Pedestal Assembly

Supplies:

• • Small weigh boat 

  • Nylon threaded rod 

  • Smooth Cast 300-Fast Setting 

  • Stage with clips 

  • Dremel 

  • Sharpie fine tip 

  • 00-90 Brass screws with Hex heads (2) 

  • 00-90 Brass Hex nuts (2) 

  • turning tool 

  • Flat head pliers 

  • Ultra liquid super glue​ 

Drive Assembly

Supplies

Part 1- Threading the 23 g from the bundle into the disc

• • Sharpie fine tip 

  • Stage with clips 

  • Disc 

  • Bundle 

  • Putty 

  • Flat head pliers OR ceramic tweezers 

Part 2- Acrylic the bundle to the disc and attach the EIB

Part 3- Cutting down the 23g​

Testing Impedences and Gold Plating: NanoZ

Supplies

• • Nano Z and USB hookup 

  • The Stand and the moveable contracption 

  • You need the stand with the ground wire to hold the saline/gold plating solution 

  • Tape 

  • Computer with windows to run the nano Z program 

  • Sonifier 

  • Distilled water 

  • Drive 

Directions

• 1. You want to take initial readings of your tetrodes to see if they are appropriate to gold plate or if you need to tweak or fix any of them 

  2. To do this, you want to use the saline solution (very much like the liquid that is in the brain) and place it in the stand with the ground wire 

  3. You want to attach your drive to the nano Z omnetics connector 

  4. You then want to position the drive so that it is able to be submersed into the saline solution without hitting any of the walls. 

  5. Lower the drive and tape the stand down. Raise it back up so that the ends of the tetrode are a millimeter into the solution 

  6. Attach the ground wire 

  7. Connect the nanoZ to the computer and boot up the software 

  8. To test the impedences make sure that your Device is the correct one according to which EIB you are using 

  9. For the White Matter EIB be sure to use WM-ADT-B1 

  10. Select Test Impedences and run the test for 1 run pausing for 1 second 

  11. The first data point you get is the reference to the ground, then 18 and 19 are also ground references as well 

  12. Ideally the results you want to see are impedences that are below sub 4 MOhm 

  13. If there are many channels that are not there is 2 things you can try: first push down the pins in question to make sure there is a connection between the pin and the tetrode 

  14. Is to blow off the dust by applying a slide positive charge to blast off the dust 

  15. To do this, set the plating current to +0.050 and do 1 run, pausing for 1 second 

  16. Test the impedences again and you should see that the impedences have dropped significantly 

  17. Once the impedences are all relatively low then you can begin the gold plating process 

  18. This time, instead of using the saline solution, you want to use the gold plating solution to attract gold particles onto the tetrodes in order to lower the impedences by a lot 

  19. The reason we want a low impedence is because over time after the drive is implanted, we start to see that the impedences will rise so we want to start low so we can get good readings with ephys 

  20. So follow the same steps as above being very careful when you connect the EIB to the omnetics connector (rock it back and forth carefully) 

  21. It is all the same process except this time you want to use the EC Electroplate tab and MAKE sure that the plating current is at a -0.050 this time in order to attract the gold particles which have a positive charge 

  22. The Target= starts at about 350 then you want to get it to be at about 200 KOhm, you want it at 302 Hz, for 5 runs, Interval is 2 seconds and pausing for 2s. 

  23. Go ahead and autoplate as many times in order to get the impedence down to 200 KOhm 

  24. After the gold plating session for the day, make sure all the files are saved to drop box the make sure that you use the sonic fier to clean off any excess gold, dip it in for about 3 seconds each time (2 times) 

  25. The last step is to make sure that the stand with the ground wire connected to it is rinsed out with distilled water so that there is no leftover residue for next times use.